1. Field of the Invention
This invention relates to a method for the detection of a target nucleic acid in the cytoplasm of a living cell. More specifically, it relates to a method for the detection of a target nucleic acid existing in the cytoplasm of a living cell through hybridization by using probes labeled with fluorescent dyes.
2. Related Background Art
Hybridization is known as one of the methods to detect a nucleic acid having a specified base sequence (hereafter referred to as "target nucleic acid"). This method employs an oligonucleotide probe having a base sequence capable of hybridizing to the target nucleic acid as a detection probe to form a hybrid, and performs detection of the target nucleic acid by detecting the hybrid through various detection means.
Hybridization methods in the prior art, however, suffer from the drawbacks described below. Thus it will be difficult to apply them to detecting a target nucleic acid in the cytoplasm of a living cell. In other words, when a detection probe is introduced into the cytoplasm, it will rapidly move to the nucleus. This makes it difficult to allow the probe to form a hybrid with the target nucleic acid existing in the cytoplasm. In addition, the detection probe, which has been introduced into the cytoplasm, or the hybrid between the detection probe and the target nucleic acid is rapidly digested by various kinds of nuclease existing in the cytoplasm, which renders the detection of the target nucleic acid difficult.